Interface standards between a radio equipment control (REC) and a radio equipment (RE) which compose a base station apparatus include CPRI (Common Public Radio Interface) standards (registered trademark).
Patent Literature 1 discloses a technique related to an interface between a radio equipment control and a radio equipment. Patent Literature 1 discloses a base station apparatus which connects the radio equipment control and the radio equipment via a cable (transmission link).
In addition, Patent Literature 2 discloses a data communication apparatus which switches a dummy clock from a regular synchronization clock when it is determined that serial data communication is not executed between first communication means and second communication means.